| Message ID | 20210618183017.3340769-1-olteanv@gmail.com |
|---|---|
| Headers | show |
| Series | Improvement for DSA cross-chip setups | expand |
On 6/18/2021 11:30 AM, Vladimir Oltean wrote: > From: Vladimir Oltean <vladimir.oltean@nxp.com> > > The cross-chip notifiers work by comparing each ds->index against the > info->sw_index value from the notifier. The ds->index is retrieved from > the device tree dsa,member property. > > If a single tree cross-chip topology does not declare unique switch IDs, > this will result in hard-to-debug issues/voodoo effects such as the > cross-chip notifier for one switch port also matching the port with the > same number from another switch. > > Check in dsa_switch_parse_member_of() whether the DSA switch tree > contains a DSA switch with the index we're preparing to add, before > actually adding it. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> -- Florian
On 6/18/2021 11:30 AM, Vladimir Oltean wrote: > From: Vladimir Oltean <vladimir.oltean@nxp.com> > > Currently, the notifier for adding a multicast MAC address matches on > the targeted port and on all DSA links in the system, be they upstream > or downstream links. > > This leads to a considerable amount of useless traffic. > > Consider this daisy chain topology, and a MDB add notifier emitted on > sw0p0. It matches on sw0p0, sw0p3, sw1p3 and sw2p4. > > sw0p0 sw0p1 sw0p2 sw0p3 sw0p4 > [ user ] [ user ] [ user ] [ dsa ] [ cpu ] > [ x ] [ ] [ ] [ x ] [ ] > | > +---------+ > | > sw1p0 sw1p1 sw1p2 sw1p3 sw1p4 > [ user ] [ user ] [ user ] [ dsa ] [ dsa ] > [ ] [ ] [ ] [ x ] [ x ] > | > +---------+ > | > sw2p0 sw2p1 sw2p2 sw2p3 sw2p4 > [ user ] [ user ] [ user ] [ user ] [ dsa ] > [ ] [ ] [ ] [ ] [ x ] > > But switch 0 has no reason to send the multicast traffic for that MAC > address on sw0p3, which is how it reaches switches 1 and 2. Those > switches don't expect, according to the user configuration, to receive > this multicast address from switch 1, and they will drop it anyway, > because the only valid destination is the port they received it on. > They only need to configure themselves to deliver that multicast address > _towards_ switch 1, where the MDB entry is installed. > > Similarly, switch 1 should not send this multicast traffic towards > sw1p3, because that is how it reaches switch 2. > > With this change, the heat map for this MDB notifier changes as follows: > > sw0p0 sw0p1 sw0p2 sw0p3 sw0p4 > [ user ] [ user ] [ user ] [ dsa ] [ cpu ] > [ x ] [ ] [ ] [ ] [ ] > | > +---------+ > | > sw1p0 sw1p1 sw1p2 sw1p3 sw1p4 > [ user ] [ user ] [ user ] [ dsa ] [ dsa ] > [ ] [ ] [ ] [ ] [ x ] > | > +---------+ > | > sw2p0 sw2p1 sw2p2 sw2p3 sw2p4 > [ user ] [ user ] [ user ] [ user ] [ dsa ] > [ ] [ ] [ ] [ ] [ x ] > > Now the mdb notifier behaves the same as the fdb notifier. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> -- Florian
On 6/18/2021 11:30 AM, Vladimir Oltean wrote: > From: Vladimir Oltean <vladimir.oltean@nxp.com> > > dsa_slave_change_mtu() calls dsa_port_mtu_change() twice: > - it sends a cross-chip notifier with the MTU of the CPU port which is > used to update the DSA links. > - it sends one targeted MTU notifier which is supposed to only match the > user port on which we are changing the MTU. The "propagate_upstream" > variable is used here to bypass the cross-chip notifier system from > switch.c > > But due to a mistake, the second, targeted notifier matches not only on > the user port, but also on the DSA link which is a member of the same > switch, if that exists. > > And because the DSA links of the entire dst were programmed in a > previous round to the largest_mtu via a "propagate_upstream == true" > notification, then the dsa_port_mtu_change(propagate_upstream == false) > call that is immediately upcoming will break the MTU on the one DSA link > which is chip-wise local to the dp whose MTU is changing right now. > > Example given this daisy chain topology: > > sw0p0 sw0p1 sw0p2 sw0p3 sw0p4 > [ cpu ] [ user ] [ user ] [ dsa ] [ user ] > [ x ] [ ] [ ] [ x ] [ ] > | > +---------+ > | > sw1p0 sw1p1 sw1p2 sw1p3 sw1p4 > [ user ] [ user ] [ user ] [ dsa ] [ dsa ] > [ ] [ ] [ ] [ ] [ x ] > > ip link set sw0p1 mtu 9000 > ip link set sw1p1 mtu 9000 # at this stage, sw0p1 and sw1p1 can talk > # to one another using jumbo frames > ip link set sw0p2 mtu 1500 # this programs the sw0p3 DSA link first to > # the largest_mtu of 9000, then reprograms it to > # 1500 with the "propagate_upstream == false" > # notifier, breaking communication between > # sw0p1 and sw1p1 > > To escape from this situation, make the targeted match really match on a > single port - the user port, and rename the "propagate_upstream" > variable to "targeted_match" to clarify the intention and avoid future > issues. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> -- Florian
On Fri, Jun 18, 2021 at 09:30:12PM +0300, Vladimir Oltean wrote: > From: Vladimir Oltean <vladimir.oltean@nxp.com> > > The cross-chip notifiers work by comparing each ds->index against the > info->sw_index value from the notifier. The ds->index is retrieved from > the device tree dsa,member property. > > If a single tree cross-chip topology does not declare unique switch IDs, > this will result in hard-to-debug issues/voodoo effects such as the > cross-chip notifier for one switch port also matching the port with the > same number from another switch. > > Check in dsa_switch_parse_member_of() whether the DSA switch tree > contains a DSA switch with the index we're preparing to add, before > actually adding it. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Andrew
From: Vladimir Oltean <vladimir.oltean@nxp.com> This series improves some aspects in multi-switch DSA tree topologies: - better device tree validation - better handling of MTU changes - better handling of multicast addresses - removal of some unused code Vladimir Oltean (6): net: dsa: assert uniqueness of dsa,member properties net: dsa: export the dsa_port_is_{user,cpu,dsa} helpers net: dsa: execute dsa_switch_mdb_add only for routing port in cross-chip topologies net: dsa: calculate the largest_mtu across all ports in the tree net: dsa: targeted MTU notifiers should only match on one port net: dsa: remove cross-chip support from the MRP notifiers include/net/dsa.h | 15 ++++++++ net/dsa/dsa2.c | 22 ++++-------- net/dsa/dsa_priv.h | 4 +-- net/dsa/port.c | 4 +-- net/dsa/slave.c | 22 ++++++------ net/dsa/switch.c | 87 ++++++++-------------------------------------- 6 files changed, 53 insertions(+), 101 deletions(-)